Means for and method of securing lead-in wires in electric lamps.



No. 759,506. 7 PATENTED MAY 10 1904.

J. C. ENTRIKE N & W. S EVERETT. MEANS FOR AND METHOD OF SECURING LEAD-INWIRES IN ELECTRIC LAMPS.

APPLICATION FILED JAN. 21; 1904.

H0 MODEL.

INVENTORY,

M 8' a Wm W M W Af/omey;

W HIV/555E3- W m: nomus mins :0, PkoYo-nfna, WASHINGYON, n c

No.759,506. l PatentedMay10,190;.

UNITED STATES PATENT OFFICE.

JOHN (J. ENTRIKEN AND WILLIAM S. EVERETT, OF MALVERN, PENNSYL- VANIA,ASSIGNORS OF SEVEN-SIXTEENTHS TO CHARLES F. KINDRED, OF PHILADELPHIA,PENNSYLVANIA.

. MEANS FOR AND METHOD OF SECURING LEAD-IN WIRES IN ELECTRIC LAMPS.

SPECIFIGATIONforming part of Letters Patent No. 759,506, dated May 10,1904.

"Application filed January 21, 190A. Serial No. 190,072. (No model.)

T all whom it y COW/067': fusing the glass also fuses the thin terminalBe it known that We, JOHN C. ENTRIKEN and wires. The size of this wire,therefore, must "l/VILLIAM S. EVERETT, citizens of the Unitednecessarilybe increased in order to sufliciently States, and residentsof Malvern, county of resist the heat of the flame used in the fusing 5Chester, State of Pennsylvania, have invented operation; but, in thesecond place, when this certain new and useful Improvements in Means isdone it is found that th e glass adjacent to the for and Methods ofSecuring Lead-In Wires end of the terminal section becomes cracked in 55 in Electric Lamps, of which the following is a cooling, therebybreaking the seal, and thus specification. destroying the vacuum.

IO Our invention relates to electric lights, such We have discovered ameans and method as incandescent electric lights, and more parwherebythe terminal section of'a lead-in wire ticularly to improvements in themeans and composed of two such sections-ofmetal can method of securinglead-in wires to the stem be made as thin as desired, thereby securing'of such lights. all the advantages sought to be attained by I5 Thatpart of the lead-in wire which is emthe specified method of manufacture,and in bedded and sealed in the glass of the stem of utilizing ourdiscovery We provide an electric an electric lamp must be made of ametal havlamp with a lead-in wire composed of two sec- 5 ing acoefficient of expansion substantially the tions of different metals,one having'substansame as that of glass, for reasons which are tiallythe same coeflicient of expansion as glass 20 Well-known in the art. Themetal employed and the other a different coefficient of expanfor thispurpose is platinum or an alloy of sion, which obviates the objectionshereinbeplatinum with one of the platinum group. fore specified.

The cost of such metal is very high and eon- Our invention thereforeconsists in the novel 'stantly increasing, and consequently attemptsmeans of securing a lead-in wire to electric 5 have been made to reducethe amount of platilamps and in the novel method of manufacnum necessaryfor the purpose by reducing the ture as hereinafter described, withreference diameter of the wire as Well as its length. to theaccompanying drawings, and'more par- One plan proposed is that whereinthe lead-in 'ticularly pointed out in the claims. wire is composed oftwo metals having diifer- In the drawings, Figure 1 is a side eleva- 3ent coefficients of expansion, one of them, such tion of an electriclamp embodying our invenas platinum, having substantially the samecotion. Fig. 2 is a central vertical section of eflicient of expansionas glass. The platinum the stem thereof. Fig. 3 is a similar section 0section in such construction is made of miniat right angles thereto.Figs. 4 and 5 are mum length and thickness and joined or fused bothviews in elevation, showing steps in our 35 to the other metal sectionwhich forms the new method of sealing the lead-in Wire in terminal forsupporting the filament, and both the stem; and Fig. 6 is aperspectiveview of sections are sealed in the glass stem. This the protecting-cappreferably used in such 5 plan enables the reduction in the amount ofmethod. platinum to a very great extent; but there ex- Referring to thedrawings, in which the 4 ist practical objections which inhibit its use.same reference characters relate to the same In the first place when theterminal section of or corresponding parts in all the views, the thelead-in wire is made sufliciently thin for lamp-bulb 1, in which thevacuum is mainthe purpose it has been found to be impossible tained, isprovided 'with the usual stem 2, to conduct the sealing and compressingsteps through which pass the conductor-Wires 7 45 without destroying theterminal section, be- To each of these wires is joined or fused a causewhen the small end portion of the glass lead-in wire composed ofplatinum or other stem is heated and then compressed to seal equivalentmetal or alloy, to each of which is the wires therein the high heatnecessary for fused the terminal section 5 of the lead-in wire,composed, preferably, of copper or some cheaper metal than platinum,such terminal sections extending through the bulb end of the stem. Theshort section 6 of platinum is embedded and sealed in the lower portion3 of the glass stem, the joint between said short section and theterminal section lying, preferably, just within the mass of glass 3,from which extendsalimited portion 4 of the glass stem, forming a recessterminating the stem at its bulb end and the wall of which is free fromcontact with the terminal sections.

In producing the construction described we direct the flame for fusingthe glass against a limited area of the stem inclosing the platinumsection in such manner as to prevent it from coming in contact with theterminal sections 5, thus avoiding such undue or high heating of thelatter sections as would tend to fuse the same, and to better effectthis purpose wc -pre fer to use a protecting perforated flanged cap 8 ofoblong shape, which is placed in the lower end of the stem 2, supportedin holders 10, mounted on the usual carrier, as shown in Figs. 4: and 5,the flange of which rests against the lower end of the stem and is heldthere by any suitable means. Through the perforation in the cap thewires 5 pass and are therefore inclosed by the said cap, preventing theflame from the gas-jet 9 from coming in contact therewith. WVhen theglass is sufficiently heated, the usual compression is employed tocompress the glass and embed the sections of the lead-in wire therein,the cap 8 serving to prevent the bulb end t of the stem from beingmassed together, and thereby forming a recess at the bulb end of thestem, as seen in Fig. 5, where the stem is shown with wires attached andcap 8 removed after compression.

While we prefer to use a cap as a protector for the wires 5 during theprocess of sealing, this cap may be dispensed with if proper care istaken to direct the flame against the stem in such a way as to preventit from fusing the terminal sections 5. It is preferable, however, to soprotect the terminal wires from the flame as to keep them free fromcontact with the glass in the finished product, as this construction hasthe advantage of not only rendering the operation easier to perform, butalso of obviating the possibility of breakage of the sections 5 shouldthe latter be bent in any direction, because such bend at its point ofemergence from the glass, where liability of breakage occurs, cannot besharp enough to cause such breakage, as is the case where the bend takesplace close to the point where the wire is embedded in the glass, forthe edge of the wall of the recess prevents the sharp bending of thewires at the point where they emerge from the mass of compressed glass.The flame, it is to be noted, should be directed against a limited areaof the lower partof the stem inclosing the lead-in wires and should notbe allowed to reach below the bulb edge of the stem in order to preventits high heating action on the terminal sections, and this can always bethe better insured by protecting the terminal sections as hereinbeforedescribed or in some equivalent manner.

e claim as our invention- 1. In an electric lamp, a stem through whichthe lead-in wires pass closed at its bulb end and terminatingin a recesstherein, said leadin wires being composed of sections of differentmetals, one of which has a coefficient of expansion substanially thesame as the material of the stem and embedded therein and the otherconstituting the terminal sections united to the embedded sections andextending through the recess into'the lamp-bulb, substantially asdescribed.

2. In an electric lamp, a stem through which the lead-in wires passclosed at its bulb end and terminating in a recess therein, said leadinwires being composed of sections of platinum embedded in the mass of thestem and a metal of different coefficient of expansion eonstituting theterminal sections united to the platinum sections and extending throughthe recess into the lamp-bulb, substantially as described.

3. As an improvement in the art of securing lead-in wires to the stem ofan electric lamp, the method which consists in placing in the stemlead-in wires composed of two sections of different metals unitedtogether, one havinga coefficient of expansion substantially the same asthe material of the stem and inclosed by the stem, and the otherconstituting the terminal wires extending through the bulb end of thestem, then fusing the stem by heat applied to a limited area of the stemnear its bulb end, protecting the terminal wires against fusion duringsuch application of heat, and compressing the fused mass of the stem toembed the lead-in wires therein, substantially as described.

4. As an improvement in the art of securing lead-in wires to the stem ofan electric lamp, the method which consists in placing in the stemlead-in wires composed of two sections of different metals unitedtogether, one having a coefficient of expansion substantially the sameas the material of the stem and inclosed by the stem, and the otherconstituting the terminal wires extending through the bulb end of thestem, then fusing the stem by heat applied to a limited area of the stemnear its bulb end, applying a protecting-cap to the bulb end of the stemto prevent undue heating of the terminal sections, and compressing thefused mass of the stem to embed the leadin wires therein, substantiallyas described.

5. As an improvement in the art of securing lead-in wires to the stem ofan electric lamp, the method which consists in applying to the stemlead-in wires composed of two united sections of different metals, oneof said metals consisting of platinum forming sections to be embedded inthe glass of the stem when sealed, and the other of a differentcoefficient of expansion constituting the terminal sections extendingthrough the end of the stem into the bulb, applying heat to a limitedarea of the stem surrounding said platinum sections to fuse that portionof the stem, protecting the terminal sections against fusion by saidheat, and compressing the fused portion of the stem to embed the wirestherein, substantially as described.

6. As an improvement in the art of securing lead-in wires to the stem ofan electric lamp, the method which consists in applying to the stemlead-in wires composed of two united sections of difierent metals, oneof said metals having substantially the same coefficient of expansion asglass, and forming the sections to be embedded in the glass of the stemwhen sealed, and the other of a dilferent coeflicient ofexpansion'constituting the terminal sections extending through the steminto the bulb, directing a flame against a limited area of the stemabove the end of the same and out of contact with the terminal sections,and compressing the fused portion to embed the wires therein,substantially as described.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

JOHN C. ENTRIKEN. WILLIAM S. EVERETT.

Witnesses:

G. H. EDWARDS, J. FOREMAN Cox.

